I could change it so activating the Sine behavior uses the value at the time of activation, but I feel it's likely this could break existing projects that deactivate and reactivate to "pause" the behavior. So closing as won't fix for now - easy workaround is to set a negative width in the layout view instead of setting on start of layout. Let me know if there's anything else you think should be done about this.

Thanks for the detailed reply - it makes sense why it's not a good idea to fix. As some context this was being used in dynamically created GUI (like pause screens and end of level screens) to create a 'continue arrow' and a 'back arrow'. Hence the flipping.